There are currently around 202 known species of moray eels, divided among 16 genera. These genera fall into the two sub-families of Muraeninae and Uropterygiinae, which can be distinguished by the location of their fins. In Muraeninae the dorsal fin is found near the gill slits and runs down the back of the eel, while the anal fin is behind the anus. The Uropterygiinnae, on the other hand, are defined by both their dorsal and anal fin being located at the end of their tails. Though this distinction can be seen between the two sub-families, there are still many varieties of genera within Muraeninae and Uropterygiinae. Of these, the genus Gymnothorax is by far the broadest, including more than half of the total number of species.